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Chapter 21 Global Climate Change

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Presentation on theme: "Chapter 21 Global Climate Change"— Presentation transcript:

1 Chapter 21 Global Climate Change

2 Overview of Chapter 21 Introduction to Climate Change
Causes of Global Climate Change Effects of Climate Change Melting Ice and Rising Sea Level Changes in Precipitation Patterns Effects on Organisms Effects on Human Health Effects on Agriculture Dealing with Global Climate Change

3 Introduction to Climate Change- Mean Annual Global Temperature 1960-2005

4 Climate Change Terminology
Greenhouse Gas Gas that absorbs infrared radiation Ex: Carbon dioxide, methane, nitrous oxide, chlorofluorocarbons and tropospheric ozone Positive Feedback Change in some condition triggers a response that intensifies the changed condition Infrared Radiation Radiation that has a wavelength that is longer than that of visible light, but shorter than that of radio waves Greenhouse Effect Increase of heat in a system where energy enters (often as light), is absorbed as heat, and released sometime later

5 Introduction to Climate Change
Evidence for Climate Change 11 of the 12 years between 1995 and 2006 were among the twelve warmest years since the mid-1800s Phenological spring in N. hemisphere now comes 6 days earlier Warming is not due to natural causes Human produced greenhouse gases are most plausible explanation

6 Causes of Climate Change
Greenhouse gas concentrations increasing

7 Causes of Climate Change
Increased concentration of CO2 (right) Burning fossil fuels in cars, industry and homes Deforestation Burning of forests

8 Greenhouse Effect

9 Other Pollutants Cool the Atmosphere
Atmospheric Aerosols tend to cool the atmosphere Both human and natural sources Tiny particles that remain in troposphere for weeks or months Contain many chemicals, but often contain sulfur Complicates models of climate change

10 Climate Models Climate affected by:
winds, clouds, ocean currents, and albedo Used to explore past climate events Advanced models can project future warming events Models are only as good as the data and law used to program them They have limitations

11 Climate Models

12 Effects of Global Climate Change
Ocean as CO2 sink - excess CO2 is starting to harm ocean life

13 Effects of Global Climate Change- Melting Ice and Rising Sea Levels
Sea level rise caused in 2 ways Thermal Expansion Water expands as it warms Melting of land ice Retreat of glacier and thinning of ice at the poles Melting has positive feedback Increased melting decreases ice, which decreases albedo leading to further warming

14 Melting Ice and Rising Sea Levels
1957 1998

15 Case-In-Point Impacts in Fragile Areas
Eskimo Inuit live traditional life dictated by freezing climate Climate change is altering their existence Wildlife are smaller or displaced Reduced snow cover and shorter river ice seasons Thawing of permafrost (right)

16 Effects of Global Climate Change- Changing Precipitation Patterns
Some areas will get more water, some areas will have greater droughts Ex: Hurricanes will likely get stronger

17 Effects of Global Climate Change- Effects on Organisms
Zooplankton in parts of California Current have decreased by 80% since 1951 Effecting entire food chain Decline in krill around Antarctica Caused decrease in penguin populations Species have shifted their geographic range Migrating birds are returning to summer homes earlier Food is not available at this time

18 Effects on Organisms - Coral Reefs
Coral reefs can be bleached (right) due to increase in water temperature Affects coral symbiotes and makes them more susceptible to diseases to which they would otherwise be immune

19 Effect on Organisms - Vegetation Beech Tree Range

20 Effects on Human Health
Increased number of heat-related illnesses and deaths

21 Effects on Agriculture
Difficult to anticipate Productivity will increase in some areas and decrease in others Rise in sea level will inundate flood plains and river valleys (lush farmland) Effect on pests is unknown Warmer temperatures will decrease soil moisture- requiring more irrigation Location (i.e. elevation and altitude) where certain crops can be grown may have to change

22 International Implications of Climate Change
Developed vs. Developing countries Differing self-interests Differing ability to meet the challenges of climate change

23 Dealing with Global Climate Change
To avoid the worst of climate change, CO2 levels must be stabilized at 550ppm 50% higher than current levels Two ways to attempt to manage climate change Mitigation Focuses on limiting greenhouse gas emissions to moderate global climate change Adaptation Focuses on learning to live with to the environmental changes and societal consequences brought about by global climate change

24 Dealing with Global Climate Change- Relationship Between Mitigation and Adaptation

25 Dealing with Global Climate Change- Mitigation
Locate/invent alternative fuels to fossil fuels Increase efficiency of cars and trucks Sequestering carbon before it is emitted Plant and Maintain trees to naturally sequester carbon

26 Dealing with Global Climate Change- Adaptation
Rising sea levels and coastal populations Move inland Construct dikes and levees Adapt to shifting agricultural zones NYC sewer line

27 International Efforts to Reduce Greenhouse Gas Emission
Kyoto Protocol Legally binding Provides operational rules on reducing greenhouse gases US and Australia have not signed it- it will be difficult to implement without US backing

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